Sexual assault on girls has become the most frequent crime in two major cities in South China's Guangdong province, according to an investigation by the provincial women's federation and court, Guangzhou Daily reported.　

The investigation uncovered sexual assault accounted for 75.34 percent among all crimes against girls. Some 2,506 girls under 18 were victims of sex crimes from 2008 to June 2011 including rape and forced prostitution. Just over half, 50.72 percent, were younger than 14 years old.

Police say the perpetrators of these crimes are often neighbors, friends, relatives and teachers. Some 65.74 percent of the victims surveyed knew their attacker - mostly aged under 20 years or above 50 - targeting girls left behind by their parents in less developed areas or those who have travelled from villages to developed areas.

Researchers cite multiple factors for the high levels of abuse, including predators preying on the vulnerable using food and puppy dogs as bait.

Long periods of absence by supposed guardians, poor parenting, bad public security, and a lack of sex education are also blamed for the rise in the crime.